<md-nav-bar nav-bar-aria-label="navigation links">
  <md-nav-item md-nav-sref="teacher.exam.single">单个出题</md-nav-item>
  <md-nav-item md-nav-sref="teacher.exam.2">批量出题</md-nav-item>
  <md-nav-item md-nav-sref="teacher.exam.3">查看题库</md-nav-item>
</md-nav-bar>
<ui-view></ui-view>